So now we know. The polling companies have fessed up: they got it wrong. The samples of voters used for their polling included too many internet-savvy young voters, more inclined to support Labour, and fewer older people, who were much less inclined to.
So, far from a late swing or shy Tory voters not revealing their true voting intentions, we now know that Labour was trailing badly all along.
The polling companies are embarrassed, and rightly so. But, worse for Labour, Ed Miliband and his inner circle were convinced that Labour was running neck and neck with the Tories, in with a shout of a score draw in May. Those who felt that Labour’s 35% strategy – that of talking to our core voters and those who already see themselves as leftwing – was doomed to failure did not have traction.
Miliband’s team honestly felt they might sneak a win, or at least be wrapped up in hung parliament negotiations after polling day.
I recall election night in Doncaster, where Miliband’s staff were in bits, so stunned were they at the exit poll that showed the Tories as the largest party, close to victory. All the back channels to set up post-election talks were in ruins.
I campaigned in many seats and the feedback we were getting on doorsteps did not match the optimism of the polls. Sadly, Miliband was unpopular as a potential prime minister – and voters were not shy to tell us. Our policies on immigration, welfare and the economy unsettled voters in both our heartlands and marginal seats.
But a further weakness encouraged by the polls was a reluctance among the leader and his team to criticise the SNP, because they believed they would have to talk to them after 8 May. So I was doing TV interviews where I was asked not to totally rule out a coalition. It was only very late in the day – too late – that Miliband tried to rectify this error.
Those of us arguing that Labour needed a tougher message on the big issues where the party lagged behind failed to get a hearing.
With the wisdom of hindsight, it is plain to see that despite our support among younger voters, it was the older voters wot won it. Labour got hammered among the over-65s. Our share of the vote in 2015 was just 23%. The Tory support was more than twice that, at 47%.
Even when we look at all over-55s, Labour still received only 26% to the Tories’ 43%. And in 2020 there will be an extra 850,000 “silver votes” cast.
Not only did older voters win this election, they will be decisive in 2020.
Yes, the pollsters should hang their heads in shame, but Labour’s top team need the courage to admit they got it badly wrong.
Labour must now debate Margaret Beckett’s report into our election defeat, which drew feedback from candidates, MPs, party staff and the public. That report comes from Labour’s grassroots. One lesson of the months leading up to May’s debacle is that Labour must absorb feedback, even unwelcome feedback, and not live in denial, fostering false hope fed by opinion polls.
Labour is keen to hear more from our members as we rebuild after May. The Beckett report suggests we must also have the courage to hear feedback from doorsteps about what the voters have to say.
That may be the hardest lesson to learn.
Published Guardian Comment is Free Tuesday 19 January 2016 16.54 GMT